In the development and manufacture of a golf club, performance testing is made by simulation-analyzing a test swing with a computer. The test swing may be performed by persons, while as disclosed in Japanese Patent Application Nos. 07-336153 filed Nov. 29, 1995, 08-019176 filed Feb. 5, 1996, 2000-202871 filed Dec. 22, 1998 and 2005-262515 filed Sep. 9, 2005, the disclosures of which are incorporated herein by reference, a golf club testing machine (also referred to as a swing robot or a shot robot) that mechanically performs test swings has been developed.
The golf club testing machine disclosed in Japanese Application Nos. 07-336153 and 08-019176 includes a swing arm mechanism including a first arm analogous to a human arm, and a second arm analogous to a human wrist. The first arm and the second arm are rotated in unison with each other with a golf club held by the second arm. The first arm and the second arm rotate in the same direction, but are different from each other in position of axis of rotation. In terms of angle of rotation and rotational speed, the first arm and the second arm are independently controlled by different motors. The swing arm mechanism permits a variety of club trajectory patterns to be taken.
As holder means of the golf club, the golf club testing machine includes on the second arm a twisting mechanism driven by another motor. The twisting mechanism is analogous to a folding back motion of the human wrist. The golf club testing machine operates a manner more analogous to a human swing motion.
The golf club testing machine disclosed in Japanese Application No. 2000-202871 includes on a portion thereof a rotary mechanism analogous to human hips. The rotary mechanism is rotated in an oscillating drive in a reciprocating fashion in order to measure torque of the golf club.
The golf club testing machine, developed by the inventor of this invention and disclosed in Application No. 2005-262515, includes a hit assisting mechanism simulating a sway of the hips of a player, in addition to the swing arm mechanism of Application Nos. 07-336153 and 08-019176.
Japanese Patent Application No. 09-362686 filed Dec. 12, 1997, the disclosure of which is incorporated herein by reference, discloses a club holder structure of a golf club testing machine. The holder structure includes a pair of clamping members forming a barrel-like groove. With the clamping members engaged with each other, the barrel-like groove forms a through-hole having a shape similar to the outer shape of the grip of the golf club. If the end of the grip is inserted with the grip in the through-hole, the outer surface of the grip is pressed into contact with the through-hole, and the grip is held.